DM200

[windward10]

I am not sure if this is the right place to ask for help. I have searched through the forums but not found an answer that quite fits my problem.

I have had ongoing issues since I bought my Netgear DM200 modem. We have been having issues with our phone/DSL connection. We have had 14 different Engineers and heaven knows how many visits. They have now got the broadband synced and stable (we hope) but my connection speed does not match the sync speed using my D-Link router and DM200 as bridged modem.

I originally thought it was the D-link router at fault, as the DM 200 was showing 4.5Mbs in the stats report, but when I speed test it is showing a regular drop off of nearly 1 meg to 3.6Mbps

My set up is :-
Netgear DM200 modem in bridge mode.
D-Link DSL 880L router on PPoE

Network - ethernet direct - to Laptop running windows 10

With a BT Homehub 4 I get 4.5 Mbps 0.8 Mbps up ping latency 70-90
With a BT Homehub 5 I get 4.5 Mbps 0.8 Mbps up ping latency 70-90

With the D-link I get 3.6 Mbps Down & 0.5 Mbps up ping latency 70-115

We are told that, as we are a rural site on twin copper wires the best we will get it 4.5Mbps which is what we got average for a year or so on a BT HH5 before the line broke down. BT think they have fixed the problem and the connection seems stable. The sync speed measured from the exchange to the home is 4.3-4.5, but the throughput speed is slow on the D-Link. Trouble is I need the advanced firewall setting for our home business.

The problem for me is why I get a steady 4.5Mbs (avg) from 2 inferior() routers, but only get 3.6Mbs (max) from the DM200? 

General setup details

Region located? ----- UK, Cumbria
Are you wired or wireless connected to the router? ----- Wired

Has a Factory Reset been performed? ----- yes and firmware updated
Was a Factory Reset performed before and after any firmware updates then set up from scratch? ----- Yes   

Check cable between Modem and Router, swap out to be sure. Link> Cat6 is recommended. ----- All cables swapped, but as all are less than 1.5m long they are Cat5e. The speeds I get with the BT (British Telecom) router have been tested with the same cables, so cabling is not an issue with a cheap BT router, so why should it be with a D-Link one.
Check ISP MTU requirements, Cable is usually 1500, DSL is around 1492 down to 1472. Call the ISP and ask. Link>Checking MTU Values-----MTU is set 1500 - BT requirement

Tried PPPoE and PPPoA with appropriate settings and no difference.

BT settings ADSL - MTU 1500  - VPI =0 - VCI =38 - PPPOA - VC based Mux
For DSL/PPPoE connections on the router, ensure that "Always ON" option is enabled. -----It is set to “Always ON”
If the ISP modem has a built in router, it's best to bridge the modem-----Modem bridged (but tested as router with same results)
QoS-----not set-up

[michaelkenward]

Did BT reset your IP profile after it fixed the line?

This can take a few days to automatically adjust itself.

The IP profile is a measure of the line quality. If the exchange sees a noisy line it drops the connection speed until it gets down to something it can support. This is an automated process that monitors the line over time. If the line gets better, it will gradually nudge the IP Profile up.

You can get some idea of the setting from the BT Wholesale speed test:

BTW Performance Test

[windward10]

All the BT tests have been done (14 engineers, 25 visits over 6 mths). Now that they have replaces the faulty cabling, the line is stable and yes they will adjust the profile, but the issue has been identified as the DM200 problem. All the settings are correct either with the modem bridged or as a standalone router. Compared to three other routers, with identical settings and cabling etc, the DM200 gives us 1 meg less than the other three free routers ie 3.6 Mbs instead of 4.5Mbs. Trouble is, I need to use the DM200 as a bridged modem for our D-link router and it is the weAk link in the chain. It is only 3 months old and I don't want to throw it away!

[windward10]

As an aside. The BTW speed test is really inaccurate and shows as a much slower connection than we actually have. We use Thinkbroadband as a tester as it is more acurate and records tests to my profile. Very useful when arguing with BT. The Thinkbroadband tester gives us the same results as the BT engineer with laptop so we tend to stick with it.

[michaelkenward]

It isn't that easy to unravel what is going on in your first message. Lots of extraneous information that just gets in the way. (The protocols used don't affect things.) So I may not have fully got the picture.

So, to narrow it down, you have the Netgear modem feeding into a D-link router. But what does this bit mean?

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@windward10 wrote:
Compared to three other routers, with identical settings and cabling etc, the DM200 gives us 1 meg less than the other three free routers ie 3.6 Mbs instead of 4.5Mbs.

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This reads as if the DM200 is one of these "routers". But you have already said that the DM200 is running in bridge mode, which means that it isn't acting as a router.

I assume that you mean what the manual for the DM200 describes as Modem (Modem only) mode  in the Device Mode settings.

I mention to clear up any confusion because the manual also refers to "bridge mode" in another context.

The usual problem in these circumstances is that the modem delivers "full speed" but for some reason the router is throttling the connection and delivering less out than goes in.

You say:

The Thinkbroadband tester gives us the same results as the BT engineer with laptop so we tend to stick with it.

The last time I looked BT's test is the only one that tells you the IP Profile. That's why I mentioned it.

When I run speed tests, I use about half a dozen at a go to get a better estimate. But I am on Infinity, which runs between 70-72 Mbps on most tests.

[windward10]

Hi Michael

Sorry for all the superfluous info, but I had other problems with a router previously, and was trying to provide all the info at the start

To clarify.
My goal is to have the DM200 ( in modem only mode) feeding the existing D-link router.
I have tested three old BT routers and also tried the DM200 set up as a router. The three BT routers all give around 4.5 meg, but the DM200 only tests at 3-3.6. This is the same speed as when I use the D-link and DM200 set up. Also if I use a BT router with the D-link I get 4.5 ( but this set up causes other problems, which is why I bought the Net gear modem). Do you think the DM200 is faulty?

[michaelkenward]

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@windward10 wrote:

I have tested three old BT routers and also tried the DM200 set up as a router.

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Does BT supply routers? Should that be three old BT modem-routers? As in the Homehubs you mentioned before?

I assume that you ditched the Homehub because you wanted something that would feed a router. The Homehub is infamous for not being able to operate in modem only (or bridged) mode. Probably too late now, but a wifi access point after the Homehub might have been a simpler solution.

The only way to compare a Homehub with a Netgear modem is to check the speed out of the modem, before any router is involved.

Is that what you are doing to get 3-3.6 Mbps?

If you get the same speed with the Homehub plus dLink combination as you get with the DM200 plus dLink combination this sort of points the finger at the dLink device.

I assume that earlier references to the D-Link DSL 880L should be D-Link DIR-880L. I (or Google) can't find the D-Link DSL 880L. That might even convert into a wifi access point, but that would not get around the speed issue.

 

[windward10]

Sorry you are correct. They are Home hubs and yes they won't operate in bridged mode.

I bought the DIR880L in error . I needed a router with firewall options that would suit our credit card needs, but stupidly missed it was a router only and needed a separate modem, so I bought the Net gear DM200.

I can't use the home hubs as the firewall options are poor and can't use them bridged. The Dir880l is too expensive for me to junk and when tested with a dodgy homehub dmz setup gives the same 4.5meg, but the dchp doesn't work properly, hence the need for a separate modem.

The only way I have been able to test the DM200 is to factory reset, and set up as a.standalone router. This gives the 3.6 meg which is why I think the Net gear is the sticking point.

[michaelkenward]

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@windward10 wrote:

I can't use the home hubs as the firewall options are poor and can't use them bridged.

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If that is your concern, count me out. We are in mystical territory.

Your understanding of security and firewalls is at variance with my own experience. I don't do paranoia. I just stick to sensible practice. An Internet user since they invented the thing, I have yet to lose a penny to dodgy firewalls.

[windward10]

Any suggestions on how to test the throughput speed on the DM200 when it is in modem only mode.

In the Internet info section of the modems software I can see that the sync speed of the adsl connection is nearly 5Mbps. However if it is a problem with a faulty modem, as all the tests seem to show,  I need to see what the modem output(?) is?

[windward10]

Unfortunately after rigorous testing I have discovered that the DM200 is the faulty link and is slowing down our connection. I am really dissappointed and find Netgears warranty information awful. The webpage directs you around in circles and I am unable to find out the warranty details for my particular model. I will have to take this up through Amazon, but will avoid Netgear's equipment in future.

[KKorkky]

There is a known issue of High CPU with the DM200. One of the monitoring processes "Lan_port_monitor" consumes CPU . It may be because it runs every 30ms (I would have thought once evey 5 secs would suffice in a domestic enviornment would suffice) I have found by telnetting in and killing the process the CPU falls back to normal levels. I have to do this every time the unit restarts.

The command I use is "Kill -9 1515" BE VERY CAREFULL as "1515" represents the Process ID in my unit only. Its can be found by issuing the command "ps" when telnetted it.